Switching valve



c. D. HARKLAU ETAL 3,276,381

Oct. 4, 1966 SWITCHING VALVE 2 Sheets-Sheet 1 Filed ,Feb. 2'7, 1964 ,QI'TORA/EVS' Oct. 4, 1966 c. 0. HARKLAU ETAL 3,

SWITCHING VALVE Filed Feb. 27, 1964 2 Sheets-Sheet 2 INVENTORS mewau a MfkA/Ifl leog Efiz. MBA/140! United' States Patent Office 3,276,381 Patented Oct. 4, 1966 3,276,381 SWITCHING VALVE Carroll D. Harldau and Roger L. Haritlau, Gowrie, Iowa, assignors to Albert W. Vaudt, Gowrie, Iowa Filed Feb. 27, 1964, Bar. No. 347,906 8 Claims. (Cl. 103-44) This invention relates to an automatic switching valve and in particular to a valve which is operated by fluid means. The switching valve of this invention has many diverse uses, but is particularly well suited for use as a pump prime mover.

It is one of the objects of this invention to provide a switching valve which may be used as a pump wherein the valve assembly is completely isolated from the material being discharged by the pump.

Another object of this invention is to provide a switching valve which may be used as a pump wherein diaphragm means separates the valve from the fluid material being discharged.

Accordingly, it is another object of this invention to provide a switching valve for use in a pump machine wherein all types of fluid materials may be pumped.

Also, it is an object of this invention to provide a switching valve used in a pump combination wherein extremely high pressures may be created at the point of discharge.

A still further object of this invention is to provide a switching valve having a minimum number of moving parts.

A particular object of this invention is to provide a switching valve having a pair of pistons connected to a movable shaft which extends into a pair of cylinders wherein as the shaft moves the full length of its stroke in either direction, the direction of flow of fluid into each of the cylinders is reversed thereby assuring continuous uninterrupted operation of the switching valve.

Another particular object of this invention is to provide an airless pump for spraying paint or the like.

Another particular object of this invention is to provide a pump which will develop sufficient pressure to move liquid cleaning solutions in lieu of gas or steam materials.

A still further object of this invention is to provide a switching valve which may be operated by either a liquid or a gas pressure source.

A further object of this invention is to provide a switching valve which is simple in design, economical to manufacture and refined in appearance.

This invention consists in the construction, arrangements, and combination of the various parts of the device, whereby the objects contemplated 'are attained as hereinafter more fully set forth, specifically pointed out in the claims, and illustrated in the accompanying drawings, in which:

FIG. 1 is a side elevation view, partially in cross-section of the switching valve pump illustrated in FIG. 3;

FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1;

FIG. 3 is a perspective view of the switching valve P p;

FIG. 4 is a fragmentary cross-sectional view similar to FIG. 2, but of only the valve body with the spools moved to their righthand position;

FIG. 5 is a fragmentary plan view of the valve body only and showing in phantom the inlet passageway and the associated spool moved to its righthand position permitting communication with the lefthand cylinder chamber;

FIG. 6 is a view similar to FIG. 5 but showing the spool associated with the inlet passageway moved to its lefthand position to permit communication with the righthand cylinder chamber; and

FIG. 7 is a schematic view of the switching valve used in a pump system.

The switching valve mechanism of this invention is shown in FIG. 3 in a pump combination referred to generally by the reference numeral 10. Basically, the pump 10 comprises a valve head 12 having oppositely disposed cylinders 14 and 16 on two sides thereof. At the outer ends of the cylinders 14 and 16, head assemblies 18 and 20 are respectively secured.

The valve body 12, as shown in FIG. 1, is provided with an inlet passageway 22 and an outlet passageway 24. Extending from the inlet passageway 22 in opposite directions into the cylinders 14 and 16 respectively are passageways 26 and 28. Similarly, the outlet passageway 24 has a passageway 30 extending into the cylinder 14 and a passageway 32 connecting with the cylinder 16. Intersecting the passageways 26 and 28 is a bore 34 which is parallel to a bore 36 intersecting the passageways 30 and 32. Received in the bores 34 and 36 are spool members 38 and 40 respectively. These spools are identical in construction and are cylindrical in cross-section having an annular center groove 42 which is adapted to communicate in the case of the spool 38, with the passageways 26 and 28 while the groove 42 in the spool 40 alternates in communication with the passageways 30 and 32. The outer ends of the spools 38 and 40 are connected by plate elements 44 and 45 which are held to the spool ends by cap screws 46. Since the length of the spools 38 and 40 is greater than the corresponding dimension of the valve body 12, the spools 38 and 40 may move in either direction until one of the plate elements 44 or 45 makes contact with the adjacent side of the valve body 12. As is seen in FIG. 1, when the spools 38 and 40 are moved to the left, the inlet passageway 22 is placed in communication with the passageway 28 leading to the righthand cylinder 16 and the outlet passageway 24 is similarly placed in communication with the passageway 30 leading to the lefthand cylinder 14. Accordingly, when the spools 38 and 40 are moved to the right, as shown in FIG. 4, the outlet passageway 24 is placed in communication with the passageway 32 leading to the righthand cylinder 16 and, although not specifically shown, is obvious from FIG. 1 that the inlet passageway 22 is in communication with the passageway 26 leading to the lefthand cylinder 14.

A quartet of detent assemblies 47 are provided in the valve body 12 and include two on each side of the inlet passageway 22 and the outlet passageway 24 for engagement with annular grooves 58 in the spools 38 and 40. Each of the detent assemblies 47 include a set screw 48 in bearing engagement with a spring 50 which embraces one end of a pin 52. The pin 52 has a head portion 54 which seats on a detent ball element 56. The ball element 56 is adapted to move from engagement with the outer cylindrical surface of the spools 38 and 40 to a position within the annular grooves 58. When the spools 38 and 40 are moved to the lefthand position, the righthand detents 43 are in engagement with the annular grooves 58 in each of the spools 38 and 40 while the lefthand detents 47 are displaced from engagement with the adjacent groove 58. When the spools 38 and 40 are moved to their righthand position, as shown in FIG. 4 for instance, the reverse situation exists wherein the lefthand detents 47 are in locking engagement with the grooves 58 and the righthand detents are rendered inoperative as they ride on top of the spools 38 and 40.

A piston shaft 62 is movably mounted in the valve 10 and extends into the cylinders 14 and 16 through the plates 44 and 46. A piston 64 is mounted on the shaft in the cylinder 14 and a piston 66 in the cylinder 16. Between the inner face of the piston 64 and the valve body 12 a chamber 68 is formed in the cylinder 14 and simi- '84. Once the shaft 62 has moved to larly a chamber 70 is formed in the cylinder 16 between the inner face of the piston 66 and the outer face of the valve body. Also disposed against the inner face of each of the pistons 64 and 66 is a coil spring 72 which is adapted to bear against the adjacent plate element 44 or 45. For instance, as shown in FIG. 1, when the force between the spring 72 and the plate element 45 reaches a level suflicient to overcome the detent 47 resistance with the spools 38 and 40, the spools will be moved away from the opposing spring 72.

The head assemblies 18 and are similar in construction and each comprise half sections 80 and 82 With cavities 84 and 86 formed therein respectively and separated by a diaphragm element 88 secured between the half sections 80 and 8 2. The diaphragm element 88 completely seals the two cavities 84 and 86 from each other. The cavity 86 is adapted to be filled with fluid similar to that used in the chambers 68 and 70 of the cylinders 14 and 16, although it is contemplated that sealing rings 90 on each of the pistons 64 and 66 will eliminate leakage of oil or the like past the pistons. The outer half 80 of the head assemblies is provided with a material inlet port 90 and outlet port 92. The ports 90 and 92 are provided with check valves 94 and 96 respectively which permit respectively only the admittance and discharge of fluid from the cavity 84.

As shown in FIG. 7, each of the head assemblies 18 and 20 are connected to a material source by conduits 98 and 100. Each of the conduits are provided with check valves 102 and 104 respectively. Each of the discharge ports 92 are connected through check valves 106 to a common conduit 108.

Four head bolts 110, one at each corner of the head assemblies 18 and 20, extend the full length of the pump 10 as shown in FIG. 3 and serve to clamp the mating half sections 80 and 82 together thereby holding there between the diaphragm 88. Also the head bolts 110 secure the head assemblies 18 and 22 .to the outer ends of the cylinders 14 and 16 respectively.

The inlet conduit 22 of the valve head 12 is connected by a pipe '112 to a pump 114 which in turn is in communication with an oil sump or the like 116. The outlet passageway 24 is in turn connected by a pipe 118 which extends into the oil sump 116. An oil pass pressure re lease valve 120 is disposed between the pipes 112 and 118.

Before beginning operation of the pump 10, the cylinder chambers 68 and 70 are filled with oil or the like. Also the cavities 86 are similarly filled with a fluid such as oil. Thus, when the piston 64, as shown in FIG. I, is to its far left position, the oil in the cavity 86 will force the diaphragm 88 to its lefthand dash line position. On the other hand, when the shaft 62 moves to its far right position (not illustrated) the diaphragm 88 will move to its right-hand dash line position. Each of the material inlet ports 90 are placed in communication with a source of material products such as paint of the like.

As the pump 114 begins to force oil from the sump 116 through the pipe 112 into the inlet passageway 22 of the valve 12, the oil will move into the passageway 28 and thus into the'chamber 70 of the right-hand cylinder 16. Consequently, the piston 66 will be forced to the right and the piston 64 will force oil from the chamber 68 into the passageway and thence into the outlet passageway 24 into the pipe 118 where it is returned to the oil sump 116. Also, as the pistons 64 and 66 move to the right, the diaphragm 88 will move to its right-hand dash line position thereby permitting paint material or the like to enter the inlet port 90 and fill the now enlarged cavity its far right position, the spring 72 in the cylinder 14 will come into hearing engagement with the plate element 44 interconnecting the plungers 38 and and upon reaching a predetermined pressure will instantaneously dislodge the spools 38 and 40 from engagement with'the detent balls 56 (FIG. 2)

whereby the spools in a fraction of a second move to the far right position as shown in FIG. 4. The movement of the spools to the right-hand position reverse the flow of fluid to and from the chambers 68 and 70 whereby oil is pumped through the inlet passageway 22 (FIG. 5) and thence to the passageway 26 leading to the left-hand. cylinder chamber 68. The chamber 70 is now placed in communication with the discharge passageway 24 by the passageway 32 (FIG. 4). Thus as the pump 1 1 4 forces the piston 64 to the left the diaphragm 88 is moved to its left-hand dash line position of FIG. 1 and in turn forces the paint material or the like up through the discharge port 92. Similar operation occurs in the right-hand head assembly 20 as has been described with respect to the lefthand assembly 18. And, therefore, continuous material pressure is maintained in the outlet conduit 108 with the exception of very momentary pulsations as the pistons and shaft reverse their direction of movement as the spools 38 and 40 are actuated to reverse the flow of oil into and from the cylinder chambers 68 and 70.

When non-corrosive material products are being pumped the diaphragm element 88 may be made of rubber or the like material. However, other suitable materials may be used as required for a particular job. It is noted that all of the moving parts, namely the pistons and the spools 38 and 40, are continuously being lubricated since they are completely immersed in an oil solution.

It is to be understood that the pistons 64 and 66 may be coupled in any suitable manner to any other system in lieu of the diaphragm arrangement shown as an embodiment of the present invention.

Should, for example, the discharge pipe 108 be closed while the top 114 is operating, the oil bypass valve 120 ('FIG. 7) would function to permit oil to flow directly into the pipe 118 and back into the oil sump thereby preventing damage to the pump unit 10.

Some changes may be made in the construction and arrangement of our switching valve without departing from the real spirit and purpose of our invention, and it is our intention to cover by our claims, any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

We claim:

1. In a switching valve, comprising,

a valve body,

a cylinder disposed on one side of said valve body,

a cylinder disposed on the opposite side of said valve body from said first cylinder,

a head assembly for and separate from each of said cylinders and being disposed at the outer end of each of said cylinders from said valve body,

a plurality of detachable rods interconnecting said head assemblies whereby said valve body is held between the inner ends of said cylinders,

a movable shaft extending through said valve body into each of said cylinders,

a piston in each of said cylinders and connected to the adjacent end of said shaft,

a chamber formed in each of said cylinders between said pistons and said valve body,

inlet means adapted to be in communication with each of said chambers,

outlet means adapted to be in communication with each of said chambers,

means for simultaneously opening the inlet means to one chamber and the outlet means to the other chamber, and said last mentioned means adapted to simultaneously open the inlet means to the other chamber and the outlet means to said first chamber.

2. The valve of claim 1 and said inlet means is in communication with a fluid supply, a pump means is provided for supplying fluid from said fluid supply to said chambers through said inlet means, and said outlet means is in communication with said fluid supply whereby said fluid at times is discharged from said chambers into said fluid supply through said outlet means.

3. In a switching valve, comprising,

a valve body,

a cylinder disposed on one side of said valve body,

a cylinder disposed on the opposite side of said valve body from said first cylinder,

a movable shaft extending through said valve body into each of said cylinders,

a piston in each of said cylinders and connected to the adjacent end of said shaft,

a chamber formed in each of said cylinders between said pistons and said valve body,

inlet means in said valve body in communication with each of said chambers,

outlet means in said valve body in communication with each of said chambers,

a first valve means for alternately breaking communication between said outlet means and one chamber and said outlet means and the other chamber,

a second valve means for alternately breaking communication between said inlet means and one chamber and said inlet means and said other chamber,

actuating means for simultaneously actuating said first and second valve means to a first position for placing said one chamber in communication with said inlet means and closing said one chamber to communication with said outlet means, and also simultaneously placing the outlet means in communication with the other chamber while closing the inlet means to communication with said other chamber, and to a second position wherein simultaneously said one chamber is placed in communication with said outlet means and said one chamber is closed to communication with said inlet means, and also simultaneously said other chamber is placed in communication with said inlet means and said other chamber is closed to communication with said outlet means,

spring biased detent means in engagement with each of said first and second valve means when in said first and second positions to yieldingly limit movement of said first and second valve means between said first and second positions, and

each of said cylinders having a diaphragm therein disposed outwardly of the outer sides of each of said pistons, and the outer side of each piston and the adjacent diaphragm defining a chamber, said chamber containing fluid.

4. In a switching valve, comprising,

a valve body,

a cylinder disposed on one side of said valve body,

a cylinder disposed on the opposite side of said valve body from said first cylinder,

a movable shaft extending through said valve body into each of said cylinders,

a piston in each of said cylinders and connected to the adjacent end of said shaft,

a chamber formed in each of said cylinders between said pistons and said valve body,

inlet means in said valve body in communication with each of said chambers,

outlet means in said valve body in communication with each of said chambers,

a first valve means for alternately breaking communication between said outlet means and one chamber and said outlet means and the other chamber,

.a second valve means for alternately breaking communication between said inlet means and one chamber and said inlet means and said other chamber,

actuating means for simultaneously actuating said first and second valve means to a first position for placing said one chamber in communication with said inlet means and closing said one chamber to communication with said outlet means, and also simultaneously placing the outlet means in communication with the other chamber while closing the inlet means to communication with said other chamber, and to a second position wherein simultaneously said one chamber is placed in communication with said outlet means and said one chamber is closed to communication with said inlet means, and also simultaneously said other chamber is placed in communication with said inlet means and said other chamber is closed to communication with said outlet means,

spring biased detent means in engagement with each of said first and second valve means when in said first and second positions to yieldingly limit movement of said first and second valve means between said first and second positions, and

each of said cylinders having a diaphragm therein disposed outwardly of the outer sides of each of said pistons, and the outer side of each piston and the adjacent diaphragm defining a chamber, said chamber containing fluid, means adjacent each of said diaphragms to form an outer chamber on the opposite side thereof from said piston, each of said outer chambers having a fluid inlet and an outlet means whereby as said pistons move towards their adjacent diaphragms said fluid in said outer chambers is forced out said outlet means connected thereto and as said pistons move away from the adjacent diaphragms said outer chambers are filled with fluid through said inlet means connected thereto.

5. In a switching valve, comprising,

a valve body,

a cylinder disposed on one side of said valve body,

a cylinder disposed on the opposite side of said valve body from said first cylinder,

a movable shaft extending through said valve body into each of said cylinders,

a piston in each of said cylinders and connected to the adjacent end of said shaft,

a chamber formed in each of said cylinders between said pistons and said valve body,

inlet means in said valve body in communication with each of said chambers,

outlet means in said valve body in communication with each of said chambers,

a first valve means for alternately breaking communicationbetween said outlet means and one chamber and said outlet means and the other chamber,

a second valve means for alternately breaking communication between said inlet means and one chamber and said inlet means and said other chamber,

actuating means for simultaneously actuating said first and second valve means to a first position for placing said one chamber in communication with said inlet means and closing said one chamber to com-munication with said outlet means, and also simultaneously placing the outlet means in communication with the other chamber while closing the inlet means to communication with said other chamber, and to a second position wherein simultaneously said one chamber is placed in communication with said outlet means and said one chamber is closed to communication with said inlet means, and also simultaneously said other chamber is placed in communication with said inlet means and said other chamber is closed to communication with said outlet means,

spring biased detent means in engagement with each of said first and second valve means when in said first and second positions to yieldingly limit movement of said first and second valve means between said first and second positions, and

each of said cylinders having a diaphragm therein dispose-d outwardly of the outer sides of each of said pistons, and the outer side of each piston and the adjacent diaphragm defining a chamber, said chamber containing fluid, means adjacent each of said diaphrams to form an outer chamber on the opposite side thereof from saidpiston, each of said outer chambers having a fluid inlet and an outlet means whereby as said pistons move towards their adjacent diaphragms said fiuid in said outer chambers is forced out said outlet means connected thereto and as said pistons move away from the adjacent diaphrag-ms said outer chambers are filled with fluid through said inlet means connected thereto, the outlet means of said outer chambers are connected to a common discharge passageway.

6. In a switching valve, comprising,

a valve body,

a cylinder disposed on one side of said valve body,

a cylinder disposed on the opposite side of said valve body from said first cylinder,

a movable shaft extending through said valve body into each of said cylinders,

a piston in each of said cylinders and connected to the adjacent end of said shaft,

a chamber formed in each of said cylinders between said pistons and said valve body,

inlet means in said valve body in communication with each of said chambers,

outlet means in said valve body in communication with each of said chambers,

a first valve means for alternately breaking communication between said outlet means and one chamber and said outlet means and the other chamber,

a second valve means for alternately breaking communication between said inlet means and one chamber and said inlet means and said other chamber,

actuating means for simultaneously actuating said first and second valve means to a first position for placing said one chamber in communication with said inlet means and closing said one chamber to communication with said outlet means, and also simultaneously placing the outlet means in communication with the other chamber while closing the inlet means to communication with said other chamber, and to a second position wherein simultaneously said one chamber is placed in communication with said outlet means and said one chamber is closed to communication with said inlet means, and also simultaneously said other chamber is placed in communication with said inlet means and said other chamber is closed to communication with said outlet means,

spring biased detent means in engagement with each of said first and second valve means when in said first and second positions to yieldingly limit movement of said first and second valve means between said first and second positions, and

a head assembly is provided at the outer end of each cylinder, a diaphragm in each of said head assemblies forming a pair of cavities on opposite sides thereof, one of said cavities being in direct communication with the outer end of the adjacent cylinder, and the other cavity having a material inlet port and a material outlet port.

7. In a switching valve, comprising,

a valve body,

a cylinder disposed on one side of said valve body,

a cylinder disposed on the opposite side of said valve body from said first cylinder,

a movable shaft extending through said valve body into each of said cylinders,

a piston in each of said cylinders and connected to the adjacent end of said shaft,

a chamber formed in each of said cylinders between said pistons and said valve body,

inlet means in said valve body in communication with each of said chambers,

outlet means in said valve body in communication with each of said chambers,

a first valve means for alternately breaking communic t on between said outlet means and one chamber and said outlet means and the other chamber,

a second valve means for alternately breaking communication between said inlet means and one chamber and said inlet means and said other chamber,

actuating means for simultaneously actuating said first and second valve means to a first position for placing said one chamber in communication with said inlet means and closing said one chamber to communication with said outlet means, and also simultaneously placing the outlet means in communication with the other chamber while closing the inlet means to communication with said other chamber, and to a second position wherein simultaneously said one chamber is placed in communication with said outlet means and said one chamber is closed to communication with said inlet means, and also simultaneously said other chamber is placed in communication with said inlet means and said other chamber is closed to communication with said outlet means,

spring biased detent means in engagement with each of said first and second valve means when in said first and second positions to y-iel-dingly limit movement of said first and second valve means between said first and second positions, and

a head assembly is provided at the outer end of each cylinder, a flexible diaphragm in each of said head assemblies forming a pair of cavities on opposite sides thereof, one of said cavities being in direct communication with the outer end of the adjacent cylinder, and the other cavity having a material inlet port and a material outlet port, said material inlet port being in communication with a material supply and the outlet port of each head assembly being connected to a common discharge conduit.

8. In a switching valve, comprising,

a valve body,

a cylinder disposed on one side of said valve body,

a cylinder disposed on the opposite side of said valve body from said first cylinder,

a movable shaft extending through said valve body into each of said cylinders,

a piston in each of said cylinders and connected to the adjacent end of said shaft,

a chamber formed in each of said cylinders between said pistons and said valve body,

inlet means in said valve body in communication with each of said chambers,

outlet means in said valve body in communication with each of said chambers,

a first valve means for alternately breaking communication between said outlet means and one chamber and said outlet means and the other chamber,

a second valve means for alternately breaking communication between said inlet means and one chamber and said inlet means and said other chamber,

actuating means for simultaneously actuating said first and second valve means to a first position for placing said one chamber in communication with said inlet means and closing said one chamber to communication with said outlet means, and also simultaneously placing the outlet means in communication with the other chamber while closing the inlet means to communication with said other chamber, and to a second .position wherein simultaneously said one chamber is placed in communication with said outlet means and said one chamber is closed to communication with said inlet means, and also simultaneously said other chamber is placed in communication with said inlet means and said other chamber is closed to communication with said outlet means,

spring biased detent means in engagement with each of said first and second valve means when in said first and second positions to yieldingly limit movement of said first and second valve means between said first and second positions, and

a head assembly is provided at the outer end of each cylinder, a :flexible diaphragm in each of said head assemblies forming a -pair of cavities on opposite sides thereof, one of said cavities being in direct communication with the outer end of the adjacent cylinder, and the other cavity having a material inlet port and a material outlet port, said material inlet port being in communication with a material supply and the outlet port of each head assembly being connected to .a common discharge conduit, and said chambers in said cylinders and said first cavity of each head assembly containing a fluid whereby as said pistons move in one direction towards one head assembly said material is forced out the outlet port 10 of the adjacent cavity by the diaphragm in said one head and when said pistons move in the opposite directions towards the other head assembly the material in the other head is forced out by its diaphragm through said outlet port in the associated cavity.

References Cited by the Examiner UNITED STATES PATENTS 1,129,362 2/ 1915 Ryder 10351 1,164,926 12/119'15 Clark 103-51 2,555,018 5/1951 Von Seggern 91-329 2,732,807 1/ 1956 Parsegian 103-44 ROBERT M. WALKER, Primary Examiner. 

3. IN A SWITCHING VALVE, COMPRISING, A VALVE BODY, A CYLINDER DISPOSED ON ONE SIDE OF SAID VALVE BODY, A CYLINDER DISPOSED ON THE OPPOSITE SIDE OF SAID VALVE BODY FROM SAID FIRST CYLINDER, A MOVABLE SHAFT EXTENDING THROUGH SAID VALVE BODY INTO EACH OF SAID CYLINDERS, A PISTON IN EACH OF SAID CYLINDERS AND CONNECTED TO THE ADJACENT END OF SAID SHAFT, A CHAMBER FORMED IN EACH OF SAID CYLINDERS BETWEEN SAID PISTONS AND SAID VALVE BODY, INLET MEANS IN SAID VALVE BODY IN COMMUNICATION WITH EACH OF SAID CHAMBERS, OUTLET MEANS IN SAID VALVE BODY IN COMMUNICATION WITH EACH OF SAID CHAMBERS, A FIRST VALVE MEANS FOR ALTERNATELY BREAKING COMMUNICATION BETWEEN SAID OUTLET MEANS AND ONE CHAMBER AND SAID OUTLET MEANS AND THE OTHER CHAMBER, A SECOND VALVE MEANS FOR ALTERNATELY BREAKING COMMUNICATION BETWEEN SAID INLET MEANS AND ONE CHAMBER AND SAID INLET MEANS AND SAID OTHER CHAMBER, ACTUATING MEANS FOR SIMULTANEOUSLY ACTUATING SAID FIRST AND SECOND VALVE MEANS TO A FIRST POSITION FOR PLACING SAID ONE CHAMBER IN COMMUNICATION WITH SAID INLET MEANS AND CLOSING SAID ONE CHAMBER TO COMMUNICATION WITH SAID OUTLET MEANS, AND ALSO SIMULTANEOUSLY PLACING THE OUTLET MEANS IN COMMUNICATION WITH THE OTHER CHAMBER WHILE CLOSING THE INLET MEANS TO COMMUNICATION WITH SAID OTHER CHAMBER, AND TO A SECOND POSITION WHEREIN SIMULTANEOUSLY SAID ONE CHAMBER IS PLACED IN COMMUNICATION WITH SAID OUTLET MEANS AND SAID ONE CHAMBER IS CLOSED TO COMMUNICATION WITH SAID INLET MEANS, AND ALSO SIMULTANEOUSLY SAID OTHER CHAMBER IS PLACED IN COMMUNICATION WITH SAID INLET MEANS AND SAID OTHER CHAMBER IS CLOSED TO COMMUNICATION WITH SAID OUTLET MEANS, SPRING BIASED DETENT MEANS IN ENGAGEMENT WITH EACH OF SAID FIRST AND SECOND VALVE MEANS WHEN IN SAID FIRST AND SECOND POSITIONS TO YIELDINGLY LIMIT MOVEMENT OF SAID FIRST AND SECOND VALVE MEANS BETWEEN SAID FIRST AND SECOND PISITIONS, AND EACH OF SAID CYLINDERS HAVING A DIAPHRAGM THEREIN DISPOSED OUTWARDLY OF THE OUTER SIDES OF EACH OF SAID PISTONS, AND THE OUTER SIDE OF EACH PISTON AND THE ADJACENT DIAPHRAGM DEFINING A CHAMBER, SAID CHAMBER CONTAINING FLUID. 